Effect of acidification on an Arctic phytoplankton community from Disko Bay, West Greenland, supplement to: Thoisen, Christina; Riisgaard, Karen; Lundholm, Nina; Nielsen, Torkel Gissel; Hansen, Per Juel (2015): Effect of acidification on an Arctic phytoplankton community from Disko Bay, West Greenland. Marine Ecology Progress Series, 520, 21-34

• Main Authors: Thoisen, Christina, Riisgaard, Karen, Lundholm, Nina, Nielsen, Torkel Gissel, Hansen, Per Juel
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2015
• Subjects: Arctic; Bottles or small containers/Aquaria <20 L; Chaetoceros spp.; Entire community; Growth/Morphology; Laboratory experiment; Navicula granii; Navicula spp.; Navicula vanhoeffenii; Open ocean; Pelagos; Phaeocystis pouchetii; Polar; Pyramimonas sp.; Thalassiosira sp.; Figure; Treatment; Growth rate; Growth rate, standard deviation; Time in days; Percentage; Percentage, standard deviation; Species; Diameter; Frequency; Thalassiosira spp.; pH; pH, standard deviation; Salinity; Temperature, water; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Bicarbonate ion; Bicarbonate ion, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbon dioxide; Carbon dioxide, standard deviation; Carbonate system computation flag; Fugacity of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide water at sea surface temperature wet air; Alkalinity, total; Aragonite saturation state; Calcite saturation state; Experiment; Potentiometric; Coulometric titration; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Greenland; Disko Bay; Ocean acidification; Phytoplankton
• Online Access: https://dx.doi.org/10.1594/pangaea.847228; https://doi.pangaea.de/10.1594/PANGAEA.847228

Long-term measurements (i.e. months) of in situ pH have not previously been reported from the Arctic; this study shows fluctuations between pH 7.5 and 8.3 during the spring bloom 2012 in a coastal area of Disko Bay, West Greenland. The effect of acidification on phytoplankton from this area was studied at both the community and species level in experimental pH treatments within (pH 8.0, 7.7 and 7.4) and outside (pH 7.1) in situ pH. The growth rate of the phytoplankton community decreased during the experimental acidification from 0.50 ± 0.01/day (SD) at pH 8.0 to 0.22 ± 0.01/day at pH 7.1. Nevertheless, the response to acidification was species-specific and divided into 4 categories: I, least affected; II, affected only at pH 7.1; III, gradually affected and IV, highly affected. In addition, the colony size and chain length of selected species were affected by the acidification. Our findings show that coastal phytoplankton from Disko Bay is naturally exposed to pH fluctuations exceeding the experimental pH range used in most ocean acidification studies. We emphasize that studies on ocean acidification should include in situ pH before assumptions on the effect of acidification on marine organisms can be made. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2015) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation is 2015-06-01.